JMX may fail without com.sun.management.jmxremote.host with Java 8

[Lordess]

• dble version:

  2.18.09 in developing (master branch)

• preconditions:

  • JVM 8
  • java.net.preferIPv4Stack=false(default) in wrapper.conf
  • host is UNKNOWN to name service ( e.g. host named "ALOHA" , but dont have "ALOHA“ reocord in both /etc/hosts and DNS servers
  • enabled JMX in wrapper.conf
  • do NOT have set com.sun.management.jmxremote.host for JMX in wrapper.conf

• configs:

  does not matter server.xml, schema.xml or rule.xml

• steps:

  step1. Remove your host record in /etc/hosts and wipe out dns cache. Do ping( e.g. ping -c3 ALOHA) and find it failed for validation.
  step2. Start dble in normal way will get it stopped from booting. Found JMX failed to start and resulted in JVM quit.

• analysis:

  For JVM 8, in default, IPv6 in favor of IPv4. And, this difference, may cause JVM_GetHostName() doesnt work as well as in IPv4 mode.

Inet6AddressImpl.getLocalHostName()
    at impl.getLocalHostName()
    at InetAddress.getLocalHost()
    at JMXServiceURL()
    at exportMBeanServer()
    ...

• suggestion:

  Add -Dcom.sun.management.jmxremote.host=127.0.0.1 for work aroud.

[FlyingMao]

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